I have the same trouble with mine, and
I think my sender is wrong.
A little while back I changed the entire coling system (with a 180 thermostat) and installed a mechanical temp guage.
THe truck has been stable at 180 for months, so I reinstalled the electic sending unit.
BAM! Right to full hot when it warmed up.
Off to the parts stores to deal with blank looks from some of tomorrows leaders.
"A what...for a 1965? That isn't in the computer.."
